[][][MAC80211][WiFi6/7][mt76][Add HT40- capab when enable ACS]

[Description]
Add HT40- capab when enable ACS. Dafault still using HT40+.
use below command to set HT40-.
uci set wireless.radioX.channel=auto
uci set wireless.radioX.htmode=HT40-
uci commit wireless
wifi reload

[Release-log]
N/A

Change-Id: I8b88734e5f9263d91c270cd117018c49cf0418ca
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/8025741
2 files changed